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Appendix B
Configuring the Catalyst 1900 Switch
#clear mac-address-table ?
dynamic Clear 802.1d dynamic address
permanent Clear 802.1d permanent addresses
restricted Clear 802.1d restricted static address
<cr>
Setting Permanent and Static MAC Addresses
Administrators can specifically assign permanent addresses to a switch port.
These addresses are never aged out. You can do this to provide security to a
port, which means that unless you specifically configure a hardware address
to a switch port, it won't work. Administrators can also create static entries
in the switch; these entries actually create a path for a source hardware
address. This can be really restrictive, and you need to be careful when set-
ting static entries because you can basically shut your switch down if you do
not plan the configuration carefully.
Setting Permanent MAC Address Entries
You can configure a permanent MAC address to a switch port by using the
global configuration command
mac-address-table permanent [mac-address] [interface]
In the next example, the options are as follows:
Aging-time This can be used to change the age a MAC address is
allowed to stay in the filter table before being cleared.
Permanent This sets a permanent address to an interface. If the user
changes the host NIC card, then the host will not work until you change
the permanent entry address.
Restricted This is used with the static command to set a path for source
hardware addresses. Very restrictive for where a host can send a frame.
To configure a permanent hardware address to an interface, use the mac-
address-table
permanent command from global configuration mode, as
shown next:
Todd1900EN#config t
Enter configuration commands, one per line. End with CNTL/Z
Todd1900EN(config)#mac-address-table ?
aging-time Aging time of dynamic addresses
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